Addison Road, where the protesters meet, is populated with opulent Victorian villas where even the gravel in the drives is immaculately coiffured. The houses go for £4m, although "for sale" signs are rare.

Jane Morris is one of those who is happy to accuse the mayor of "inverse snobbery".

"I run an interior design business in Knightsbridge. The street is all small traders, no supermarkets. That is what gives London its character.

"It is not stopping the congestion, it is moving it."

'Politics of envy'

Michelle Weininger is also desperate to deny that the campaign is about rich people making life easier for themselves.

"It is the politics of envy. It is totally wrong. This borough is very, very mixed, there are a lot of people on low incomes in north Kensington. They will all be hit by this.

"My husband is connected to a handful of restaurants in the West End financially. They are going to be hit badly."

The protesters are ruthlessly organised

Despite the rancour towards Mr Livingstone in the crowd, he is still universally addressed as Ken. But the protesters' faces are a mask of disgust when they rail against Ken and his globetrotting missions to obtain cheap oil from leftist fellow travellers in Venezuela.

Mrs Weininger says: "If that dictator is shoving us onto public transport why is he not using it himself?"

But Mr Livingstone's spokesman later responded to this comment saying that the mayor does use public transport all the time.

The crowd is certainly not all well-to-do ladies in Hermes scarves. Closer examination shows a number of protesters with paint on their hands. And it is emulsion, not gouache.

Parody slogans

One of them is Dane Clark, who works for a property and maintenance company in Kensington and Chelsea.

"The rates are high anyway. Now you've got to add another charge. The parking is already £3 an hour. Smaller firms may go under."

It is a blunder, which acts as the Berlin Wall and cuts communities in two

Protester Gordon Taylor

These protesters, marshalled by policemen on mountain bikes, have placards and stickers that parody the congestion charge C-symbol with the slogans "Confused", "ill-Conceived" and "Costly".

A typical run of cars parked in the surrounding area might go Merc, Merc, Bentley, BMW, but the selection of cars on the go-slow is more modest, containing only the odd Porsche and Lexus.

Gordon Taylor, chairman of the West London Residents' Association, is in possession of the facts on congestion charging and they have made him a very cross man.

The go-slow was policed by slow-moving officers

"Less than 5% of the road length in the west London zone has congestion. It isn't needed.

"It is a blunder, which acts as the Berlin Wall and cuts communities in two."

DJ and prospective mayoral candidate Mike Read is at the protest to show his support.

"It is crazy to extend it because haulage people and everybody else will find alternative routes and jam up other areas. It will clog the whole place up."

As for the go-slow protest, the Transport for London spokesman says: "'No one's interests are served by organising a drive slow on a Saturday, causing congestion and delays, when people are trying to go about their business and go shopping."

He argues the central London charge has worked - traffic levels have been cut by 20%, or 70,000 fewer vehicles a day.